Hydraulic hold open device



Oct. 19, 1965 c. FLINT 3,212,122

HYDRAULIC HOLD OPEN DEVICE Filed Dec. 11, 1961 5 Sheets-Sheet 1 Oct. 19, 1965 R. c. FLINT 3,212,122

HYDRAULIC HOLD OPEN DEVICE Filed Dec. 11, 1961 3 Sheets-Sheet 2 Oct. 19, 1965 R. c. FLINT HYDRAULIC HOLD OPEN DEVICE 3 Sheets-Sheet 5 Filed Dec. 11, 1961 United States Patent C 3,212,122 HYDRAULIC HULD OPEN DEVICE Russell C. Flint, Princeton, IllL, assignor to Schlage Lock Company, San Francisco, Calif., a corporation of California Filed Dec. 11, 1961, Ser. No. 158,481 4 Claims. (Cl. 16-49) This invention relates to a door holder and, more particularly, to a hydraulic hold open device for doors.

In many instances it is desired to leave a door in an open position for certain periods of time. Particularly is this true of doors in the patient rooms of hospitals where it is desirable, at times, to leave these doors open sufficiently to provide ventilation and yet not open far enough to prevent privacy to the patient in the room. To prevent wind, drafts and the like from moving the door from the particular desired position, various friction devices have been employed in the past. However, these friction devices Wear out very quickly and their friction capacity varies constantly.

It is therefore an object of the present invention to provide a door holder in which its door holding capacity remains substantially constant.

It is a further object of the present invention to provide a hydraulic hold open device for doors.

It is a further object of the present invention to provide a hydraulic hold open device which will hold a door open in any one of its numerous open positions.

It is a further object of the present invention to provide a hydraulic hold open device which Will hold a door open in any one of its numerous open positions against the force of wind, drafts or the like, yet will allow the door to be open and closed without excessive force being applied by the person opening or closing the door.

It is a further object of the present invention to provide a hydraulic hold open device wherein the elements of said hold open device which hold the door open are substantially free of wear and maintain a substantially constant holding capacity.

The invention, both as to its organization and method of operation, taken with further objects and advantages thereof, will best be understood by reference to the following description taken in connection with the accompanying drawings, in which:

FIGURE 1 is a perspective view of a hydraulic hold open device embodying the features of the present invention mounted on a door and operatively connected to a door frame;

FIGURE 2 is a longitudinal, top cross-sectional view of the hydraulic hold open device of FIGURE 1;

FIGURE 3 is a longitudinal, top cross-sectional view of the hydraulic hold open device of FIGURE 1, illustrating the position of the piston and the paths of fluid travel as the door is being opened;

FIGURE 4 is a longitudinal, top cross-sectional View I of the hydraulic hold open device of FIGURE 1, illustrating the piston during a hold open stage; and

FIGURE 5 is a longitudinal, top cross-sectional view of the hydraulic hold open device of FIGURE 1, illustrating the position of the piston and the paths of fluid travel as the door is being closed.

Referring now to the drawings, and more particularly to FIGURE 1, the hydraulic hold open device of the present invention, referred to generally by reference numeral 20, is illustrated mounted on a door 22 and operatively connected to a door frame 24 to which the door 22 is hinged. It is the function of the hydraulic hold open device 20 to hold the door 22 in any open position against such forces as drafts, wind and the like and, also, to allow a person to conveniently open and close the door 22 as desired. The period in which the door 22 is being held in an open position by the hydraulic hold open device 20 is hereinafter referred to as the hold open stage.

The hydraulic hold open device 20 is mounted upon the door 22 by a bracket 26 and the operative cooperation between the door 22 and the hold open device 20 is effected by a pair of arms 30 and 32 pivotally connected at 34. The free end of the arm 32 is attached to a rotatable shaft 36 extending from the hydraulic hold open device 20 and the free end of the arm 30 is pivotally attached to a mounting 38 secured to the door frame 24. As the door 22 opens and the hydraulic hold open device 20 swings in an arc, the cooperative arrangement between the arms 30 and 32 causes the arm 30 to rotate the shaft 36 relative to the hydraulic hold open device 20. Likewise, when the door 22 is being closed the movement of cooperating arms 30 and 32 will rotate the shaft 36 in the opposite direction relative to the hydraulic hold open device 20. In this arrangement, the shaft 36 must be rotated as the door 22 is opened or closed. Therefore the hydraulic hold open device 20, by controlling the rotation of the shaft 36, controls the ease with which the door 22 may be opened or closed and holds the door 22 in any desired open position.

The manner in which the hydraulic hold open device 20 of the present invention controls the rotation of the shaft 36 and thereby holds the door 22 in any open position against the force of wind, drafts and the like will be considered in more detail with reference to FIGURES 2-5. The hydraulic hold open device 20 includes a main body 40 having a transverse bore 42 and a longitudinally extending piston chamber 44 which communicates with the transverse bore 42. The outer ends of the piston chamber 44 are closed by screw plugs 46 or the like. Extending through the transverse bore 42 is the shaft 36 having a pinion 48, the shaft 36 suitably journalled and capped to prevent leakage of hydraulic fluid from the hydraulic hold open device 20. The end of the shaft 36 which extends outwardly from the hydraulic hold open device 20 is, as discussed hereinbefore, connected to the arm 32.

Within the main body 40 and the longitudinal, circular cylindrical bore or piston chamber 44 is a piston 50 having piston heads 52 and 54 interconnected by a rack 56 having a plurality of gear teeth 57 in engagement with the pinion 48 of the shaft 36. In this manner rotation of the shaft 36 and the pinion 48 will cause the rack 56, and therefore the piston 50, to be correspondingly reciprocated or translated Within the piston chamber 44.

The main body 40, including the piston chamber 44 and the transverse bore 42, is filled with hydraulic fluid, such as oil or an oil substitute. It is the control of the movement of the fluid within the piston chamber 44, as will be more apparent hereinafter, which assists the device 20 in performing its intended functions.

The piston head 52 has a primary piston head passageway 60 and a secondary piston head passageway 58. The passageways 58 and 60 extend longitudinally through the piston head 52, their ends communicating with the piston chamber 44 on opposite sides of the piston head 52. A spring-biased ball valve or check valve 66 is positioned within the primary piston head passageway 60. The check valve 66 is a one-way valve in that it prevents the flow of hydraulic fluid from right to left through the primary piston head passageway 60. Furthermore, a spring 68 urges the check valve 66 into its closed position and therefore hydraulic fluid may not flow from left to right through the passageway 60 until the pressure of the hydraulic fluid on the left side of the piston head 52 is sufficiently great to overcome the force of the spring 68.

Likewise, a spring-biased ball valve or check valve 62 is positioned within the secondary piston head passageway 58. The check valve 62 is a one-way valve in that it prevents the flow of hydraulic fluid from left to right through the secondary piston head passageway 58. Furthermore, a spring 64 urges the check valve 66 into its closed position and therefore hydraulic fluid may not flow from right to left through the passageway 60 until the pressure of the hydraulic fluid on the right side of the piston head 52 is sufficiently great to overcome the force of the spring 64.

It will therefore be understood that for hydraulic fluid in the piston chamber 44 to pass from the right side of the piston head 52 to the left side of the piston head 52 it must go through the secondary piston head passageway 58. Likewise, for hydraulic fluid in the piston chamber 44 to pass from the left side of the piston head 52 to the right side of the piston head 52 it must pass through the primary piston head passageway 60.

It will be understood that the valves 62 and 66 are well known check valves and that any other check valves which will perform the same function in substantially the same manner may be employed in place of the valves 62 and 66.

The piston head 54 has a primary piston head passageway 72 and a secondary piston head passageway 70. The passageways 70 and 72 extend longitudinally through the piston head 54, their ends communicating with the piston chamber 44 on opposite sides of the piston head 54. A spring-biased ball valve or check valve 78 is positioned within the primary piston head passageway 72. The check valve 78 is a one-way valve in that it prevents the flow of hydraulic fluid from left to right through the primary piston head passageway 72. Furthermore, a spring 80 urges the check valve 78 into its closed position and therefore hydraulic fluid may not flow from right to left through the passageway 72 until the pressure of the hydraulic fluid on the right side of the piston head 54 is sufficiently great to overcome the force of the spring 80.

Likewise, a spring-biased ball valve or check valve 74 is positioned within the secondary piston head passageway 70. The check valve 74 is a one-way valve in that it prevents the flow of hydraulic fluid from right to left through the secondary piston head passageway 70. Furthermore, a spring 76 urges the check valve 74 into its closed position and therefore hydraulic fluid will not flow from left to right through the passageway 70 until the pressure of the hydraulic fluid on the left side of the piston head 54 is sufliciently great to overcome the force of the spring 76.

It will therefore be understood that for hydraulic fluid in the piston chamber 44 to pass from the right side of the piston head 54 to the left side of the piston head 54 it must go through the primary piston head passageway 72. Likewise, for hydraulic fluid in the piston chamber 44 to pass from the left side of the piston head 54 to the right side of the piston head 54 it must pass through the secondary piston head passageway 7 0.

It will be understood that the valves 74 and '78 are well known check valves and that any check valves which will perform the same function in substantially the same manner may be employed in place of the valves 74 and 78.

The hydraulic hold open device is illustrated in FIGURE 2 when the door 22 is closed. When the door 22 is opened the shaft 36 and pinion 48 are rotated in a counterclockwise direction as shown in FIGURE 3, thereby translating the piston 50 toward the right in the piston chamber 44. As the door 22 is opened the piston head 54 displaces hydraulic fluid from the right end of piston chamber 44, this displaced hydraulic fluid passing to the left end of the piston chamber 44. The solid arrows in FIGURE 3 illustrate the flow of fluid during the period in which the door 22 is being opened. The check valve 74 prevents fluid from flowing through the secondary piston head passageway 70 as the piston 50 moves toward the right. However, when the pressure of the hydraulic fluid on the right side of the piston head 54 becomes sufliciently great to overcome the force of the spring 80, this pressure being governed by the force applied to the door 22, hydraulic fluid will pass through the primary piston head passageway 72 through the check valve 78 to the other side of the piston head 54. At the piston head 52 the hydraulic fluid will not pass through the primary piston head passageway 60 because of the check valve 66, but may pass through the secondary piston head passageway 58 when the hydraulic fluid has suflicient pressure to overcome the force of the spring 64. In this manner hydraulic fluid is forced from the right end of the piston chamber 44 to the left end of the piston chamber 44 as the door 22 is being opened and the piston 50 translated toward the right.

When the door 22 has been opened to the desired point, the person releases the door and the hydraulic hold open device 20 takes over to prevent wind, drafts and the like from moving the door. FIGURE 4 illustrates the position of the piston 50 and the position of its check valves during such a hold open stage. It will be noted that in the piston head 52 the check valves 62 and 66 are maintained in the closed position by the force of springs 64 and 68, respectively. Likewise, in piston head 54 the check valves 78 and 74 are maintained in the closed position by the force of springs and 76, respectively. In this manner the piston 56 and therefore the door 22 is held in this position until suflicient force has been exerted to cause valves 66 or 78 to be opened. For this reason the passageways 60 and 72 have been referred to as the primary piston head passageways as they provide the principal control over holding the door in the desired open position.

When it is desired to close the door 22 the person exerts sufficient force against the door to overcome the force of springs 68 and 76 in the check valves 66 and 74, respectively. This force will be translated through the shaft 36 and the pinion 48 to cause the pinion 48 to rotate in a clockwise direction and translate the piston 50 toward the left in the piston chamber 44 as illustrated in FIGURE 5. In this manner hydraulic fluid will be displaced from the left end of the piston chamber 44 to the right end of the piston chamber 44. The solid arrows in FIGURE 5 illustrate the flow of hydraulic fluid as the door 22 is being closed. As the piston 50 moves toward the left the check valve 62 will remain closed and prevent the passage of fluid through the secondary piston head passageway 58. However, when the pressure of the hydraulic fluid on the left side of the piston head 52 becomes sufliciently great to overcome the force of the spring 68, this pressure being governed by the force applied to the door 22, hydraulic fluid will pass through the primary piston head passageway 60 through the check valve 66 to the other side of the piston head 52. At the piston head 54 the hydraulic fluid will not pass through the primary piston head passageway 72 because of the check valve 66, but may pass through the secondary piston head passageway 70 when the hydraulic fluid has sufficient pressure to overcome the force of the spring 76. In this manner hydraulic fluid is forced from the left end of the piston chamber 44 to the right end of the piston chamber 44 as the door 22 is being closed and the piston 50 translated toward the left.

It will be understood that the various spring-biased valves are properly adjusted to insure that the door will be held open in the desired position and yet not be difficult to open and close. Furthermore the spring-biased valves in the hydraulic hold open device 20 may be replaced with different tension check valves or adjusted to adapt the device 20 to the specific conditions in which the door 22 is to be used. Such adjustments would be within the ordinary skill of one in the art.

Furthermore, it will be understood that when the door 22 is closed the hold open device 20 will prevent wind,

drafts and the like from opening the door 22 in the same manner it held the door 22 in any desired open position. Thus a door latch is not necessary on a door operatively connected to the hydraulic hold open device 20.

It is now apparent that the hydraulic hold open device 20 of the present invention is therefore capable of holding a door in an infinite number of open positions against wind, drafts or the like and yet allows the door to be easily opened and closed. In addition, the device 20 does not contain mechanical elements which tend to deteriorate and affect its holding ability.

It will be understood that the hold open device 20 requires only one piston head 52 or 54 to hold open the door 22 in the manner described hereinbefore. Furthermore, in this respect, it will be understood that the same result may be achieved by a dash-pot type device which has a piston therein having only one piston head, that piston head being similar to piston head 52 or 54, and the piston is reciprocated within the fluid filled dash-pot in cooperation with the movement of the door 22.

While the embodiments described herein are at present considered to be preferred, it is understood that various modifications and improvements may be made therein, and it is intended to cover in the appended claims all such modifications and improvements as fall within the true spirit and scope of the invention.

What is desired to be claimed and secured by Letters Patent of the United States is:

1. A hydraulic hold open device for a door which comprises a main body having a piston chamber with hydraulic fluid, a piston in said chamber, means operatively connecting said piston to said door whereby said piston moves in said piston chamber as said door opens and closes, said piston having first and second piston heads, each of said piston heads having first and second sides, each of said piston heads having first and second passageways extending therethrough from said first side to said second side, said first and second passageways in each of said piston heads each having a spring-biased, oneway check valve therein, said valves in said first passageways preventing fluid from flowing therethrough from said first side to said second side of said piston heads and said valves in said second passageways preventing fluid from flowing therethrough from said second side to said first side of said piston heads.

2. A hydraulic hold open device for a door which comprises a main body having a piston chamber with hydraulic fluid, a piston in said chamber, means operatively connecting said piston to said door whereby said piston moves in said piston chamber as said door opens and closes, said piston having first and second piston heads, each of said first and second piston heads having a first and second side, said first piston head having first and second passageways extending therethrough from said first side to said second side of said first piston head, a first spring-biased, one-way check valve in said first passageway, said first check valve preventing hydraulic fluid from flowing from said first side of said first piston head to said second side of said first piston head, a second check valve in said second passageway, said second check valve preventing hydraulic fluid from flowing through said second passageway from said second side of said first piston head to said first side of said piston head, said second piston head having third and fourth passageways extending therethrough from said first side to said second side of said second piston head, a third spring-biased, one-way check valve in said third passageway, said third check valve preventing fluid from flowing through said second piston head from said first side of said second piston head to said second side of said second piston head, a fourth spring-biased, one-way check valve in said fourth passageway, said fourth check valve preventing fluid from flowing through said second piston head from said second side of said second piston head to said first side of said second piston head.

3. A hydraulic hold open device for a door which comprises a main body having a longitudinally extending piston chamber communicating with a transverse bore, said bore and piston chamber being filled with hydraulic fluid, a piston in said chamber, said piston comprising two piston heads interconnected by a rack containing gear teeth, a shaft extending through said transverse bore to the exterior of said main body, said shaft having a pinion thereon engaging said gear teeth of said rack, means connecting said shaft to said door whereby said shaft rotates with the movement of the door to effect movement of said piston in said piston chamber as said door opens and closes, each of said piston heads having first and second sides and first and second passageways extending therethrough from said first side to said second side, said first and second passageways in each of said piston heads each having a spring-biased, one-way check valve therein, said valves in said first passageways preventing fluid from flowing therethrough from said first side to said second side of said piston heads and said valves in said second passageways preventing fluid from flowing therethrough from said second side to said first side of said piston heads.

4. A hydraulic hold open device for a door which comprises a main body having a piston chamber with hydraulic fluid, a piston in said chamber, means operatively connecting said piston to said door whereby said piston moves in said piston chamber as said door opens and closes, said piston having first and second piston heads, each of said first and second piston heads having a first and second side, said first piston head having first and second passageways extending therethrough from said first side to said second side of said first piston head, a first valve means in said first passageway, said first valve means preventing hydraulic fluid from flowing from said first side of said first piston head to said second side of said first piston head and permitting hydraulic fluid to flow from said second side of said first piston head to said first side of said first piston head, a second valve means in said second passageway, said second valve means preventing hydraulic fluid from flowing through said second passageway from said second side of said first piston head to said first side of said piston head and permitting hydraulic fluid to flow from said first side of said first piston head to said second side of said first piston head, said second piston head having third and fourth passageways extending therethrough from said first side to said second side of said second piston head, a third valve means in said third passageway, said third valve means preventing fluid from flowing through said second piston head from said first side of said second piston head to said second side of said second piston head and permitting hydraulic fluid to flow from said second side of said second piston head to said first side of said second piston head, a fourth valve means in said fourth passageway, said fourth valve means preventing fluid from flowing through said sec-ond piston head from said second side of said second piston head to said first side of said second piston head and permitting hydraulic fluid to flow from said first side of said second piston head to said second side of said second piston head.

References Cited by the Examiner UNITED STATES PATENTS 727,051 5/03 Adams 16-62 1,123,780 1/15 Mooney 1662 1,472,870 1 1/ 23 Kettle et a1. 16--51 1,833,121 11/31 Norton 1651 1,842,831 1/32 Hunt 188-88.7 1,863,296 6/32 Chryst 188-887 2,087,350 7/37 McCann 18888.7 2,541,250 2/51 Hogg 1651 2,964,779 12/60 Gohr 16-451 (Other references on following page) 7 FOREIGN PATENTS 654,303 7/00 Cliff. 810,411 1/06 Henry. 821,714 5/06 Henry.

DONLEY I. STOCKING, Primary Examiner.

8 Gardiner. Ellis et a1. Patriquin. Engels.

M. HENSON WOOD, JR., Examiner. 

2. A HYDRAULIC HOLD OPEN DEVICE FRO A DOOR WHICH COMPRISES A MAIN BODY HAVING A PISTON CHAMBER WITH HYDRAULIC FLUID, A PISTON IN SAID CHAMBER, MEANS OPERATIVELY CONNECTING SAID PISTON TO SAID DOOR WHEREBY SAID PISTON MOVES IN SAID PISTON CHAMBER AS SAID DOOR OPENS AND CLOSES, SAID PISTON HAVING FIRST AND SECOND PISTON HEADS, EACH OF SAID FIRST AND SECOND PISTON HEADS HAVING A FIRST AND SECOND SIDE, SAID FIRST PISTON HEAD HAVING FIRST AND SECOND PASSAGEWAYS EXTENDING THERETHROUGH FROM SAID FIRST SIDE TO SAID SECOND SIDE OF SAID FRIST PISTON HEAD, A FIRS SPRING-BIASED, ONE-WAY CHECK VALVE IN SAID FIRST PASSAGEWAY, SAID FIRST CHECK VALVE PREVENTING HYDRAULIC FLUID FROM FLOWING FROM SAID FIRST SIDE OF SAID FIRST PISTON HEAD TO SAID SECOND SIDE OF SAID FIRST PISTON HEAD, A SECOND CHECK VALVE IN SAID SECOND PASSAGEWAY, SAID SECOND CHECK VALVE PREVENTING HYDRAULIC FLUID FROM FLOWING THROUGH SAID SECOND PASSAGEWAY FROM SAID SECOND SIDE OF SAID FIRST PISTON HEAD TO SAID FIRST SIDE OF SAID PISTON HEAD, SAID SECOND PISTON HEAD HAVING THIRD AND FOURTH PASSAGEWAYS EXTENDING THERETHROUGH FROM SAID FIRST SIDE TO SAID SECOND SIDE OF SAID SECOND PISTON HEAD, A THIRD SPRING-BIASED, ONE-WAY CHECK VALVE IN SAID THIRD PASSAGEWAY, SAID THIRD CHECK VALVE PREVENTING FLUID FROM FLOWING THROUGH SAID SECOND PISTON HEAD FROM SAID FIRST SIDE OF SAID SECOND PISTON HEAD TO SAID SECOND SIDE OF SAID SECOND PISTON HEAD, A FOURTH SPRING-BIASED, ONE-WAY CHECK VALVE IN SAID FOURTH PASSAGEWAY, SAID FOURTH CHECK VALVE PREVENTING FLUID FROM FLOWING THROUGH SAID SECOND PISTON HEAD FROM SAID SECOND SIDE OF SAID SECOND PISTON HEAD TO SAID FIRST SIDE OF SAID SECOND PISTON HEAD. 